Pulsed Corona Discharge for Removal of NO_x from Flue Gas

Abstract

There are many types of non-thermal discharge devices that have been investigated for environmental applications. The potential of these devices for the destruction of pollutants or toxic molecules has already been demonstrated in several contexts, such as NO_x and SO₂ in power plant flue gases [Dinelli et al. 1990; Frank and Hirano 1990] and diesel engine exhaust [Higashi et al. 1992], heavy metals [Masuda et al. 1987] and volatile organic compounds [Yamamoto et al. 1992] in industrial effluents, and chemical agents such as simulated nerve gases [Fraser et al. 1985]. These devices operate on the same basic principle: produce a discharge in which a majority of the electrical energy goes into the production of energetic electrons, rather than into gas heating. Even though the electrons are short-lived under atmospheric pressure conditions and rarely collide with a pollutant molecule, they undergo many collisions with the dominant background gas molecules, thus producing radicals that, in turn, decompose the toxic compounds. The efficiency of the approach arises from the fact that the radicals have long lifetimes and react selectively with the contaminant molecules.